A CAUTIONARY NOTE ON THE USE OF THE ALLOMETRIC FUNCTION TO ESTIMATE URBAN POPULATIONS

Use of the allometric function to estimate the number of inhabitants of urban areas, given knowledge of their land areas obtained through satellite photographs, rests as much on the stability of this function over time as on its goodness of fit to a cross section of cities at a single point in time. Using urban land and population data for four countries, the United States, Japan, Sweden, and Norway, this paper demonstrates that the function is not generally stable but rather has been subject to rapid upward shifts over the past 10 to 20 years.     

LAND‐USE DYNAMICS BEYOND THE AMERICAN URBAN FRINGE*

ABSTRACT. A deficiency common to both the historical debates over loss of agricultural land and the current discussions of urbanization and sprawl is a limited understanding of land‐use dynamics beyond the urban fringe. Data aggregated at the county level poorly capture the fine‐grained pattern of land‐use change beyond the dynamic urban‐rural interface. Furthermore, current urban‐based definitions are poorly suited to delineate these areas, and low‐density, exurban land use is difficult to measure using existing land‐cover databases. Urbanization and the conversion of once‐agricultural or other natural resource lands to other uses has traditionally been tracked using urban areas, as delimited in the U.S. census. Urban densities are typically defined as areas with more than 1,000 people per square mile, or 1.6 people per acre (U.S. Census Bureau 2000). Assuming an average of 2.5 people per housing unit, this translates to roughly 0.7 units per acre, or approximately 1 unit per 1.6 acres. The analytical units used in the census, however, both overbound and underbound areas with urban densities. About one‐third of urban areas in 1990 comprised lower‐than‐urban housing density, thanks to overbounding. But, then, one‐third of locations that had urban‐level housing densities failed to be included in urban areas as a result of underbounding, which, if counted, would have constituted another 18 million acres of urban area. An increase over time of the average number of acres required per housing unit in exurban and higher‐density locations occurred in roughly one‐third of U.S. counties from 1960 to 1990 and persisted from 1990 to 2000. In 2000 roughly 38 million acres were settled at urban densities, and nearly ten times that much land was settled at rates from low, exurban density (as low as one house per 40 acres) to higher rates (up to one per 10 acres). This represents a continuing encroachment on land previously given over to other uses—habitat or agriculture. Practitioners of natural resource management need to recognize the ubiquity of exurban development and better incorporate the fine‐scale patterns of land use beyond the urban fringe.     

城市轨道交通对土地利用变化的时空效应

定量分析轨道交通对城市内部精细土地利用复杂变化影响的时空效应,对于预测未来新建站点对土地利用的影响以及规划方案的调整与优化具有重要的指导意义。本文提出结合历史高分遥感影像与POI数据获取多时间节点精细土地利用信息的方法,并以广州市二号和八号地铁线为例,结合逐步回归模型与站点用地功能分类,从时间和空间两个维度定量研究地铁对土地利用转变的复杂影响过程与空间差异规律。结果表明,轨道交通促使站点周边低密度居住用地向商业用地、高密度居住用地等高效益土地利用方式的转变;轨道交通在规划、建设、运营不同阶段对于周边土地利用的影响呈现显著的差异规律;地铁站点对土地利用变化影响规律具有明显的空间异质性特征,与站点在城市里的位置以及站点周边的土地利用有关,对城市中心区域的影响较小,对郊区的影响主要与可用的非建设用地面积相关,而工业用地对土地利用变化具有限制作用;轨道交通还带来用地功能和性质的转变,这样的转变大多发生在地铁站点开通运营的时间点。     

大都市区城市扩张过程及形态对比分析——以东京、纽约和上海为例

大都市区化是全球城市化进程中的普遍现象,研究大都市区域城市扩张进程对理解其未来增长趋势、区域可持续发展具有重要意义。大都市区土地扩张及区域间的对比分析,以及都市区发育过程中城市扩张的一般化空间模式还未被深入理解。论文选取东京、纽约和上海3个大都市区,获取1990—2015年间3期Landsat影像数据,使用梯度和格网分析法,采用城市土地密度函数和城市扩张指数,从建设用地数量变化及其时空分布、城市形态变化等方面,多角度对比分析各城市不同阶段建设用地增长的时空差异。结果表明：① 大都市区边界仍在不断扩展,建设用地在研究期内持续增长;20多年间东京、纽约和上海的建设用地面积分别增长了63%、53%和233%;上海一直处于高强度扩张状态,而纽约的城市扩张在后期几近停滞。② 大都市区建设用地密度从中心向外呈圈层递减式分布,城市核心区和边缘区半径的增长最明显;城市形态均趋向于紧凑。③ 新增建设用地时空异质性明显。东京的远郊新城不断建设,纽约一些尚有发展潜力的区域次中心仍在扩张但速率逐渐放缓,上海的核心区外围增长剧烈并逐渐向远城区推进。④ 大都市区域扩张先后经历高速期—缓慢期—停滞期,扩张进程表现为核心区膨胀—次中心及新城建设—逐步形成稳定的多中心结构。     

中国城市群城市用地扩张时空动态特征

认识城市群城市用地扩张特征、扩张质量及景观生态效应等综合信息将有助于城市群空间高质量发展规划与决策。选取10个不同发育等级的城市群作为研究对象,综合运用城市用地扩张强度指数、城市用地扩张强度差异指数、景观扩张指数、景观格局指数,分析1990—2015年期间城市群城市用地扩张时空特征及景观生态效应,并构建人口、经济与城市用地协同发展指数,据此分析城市用地扩张中“人—地”关系协同程度。结果表明：① 1990—2015年,各个城市群城市用地面积持续增加,建成区的范围不断扩大,扩张强度呈现“上升—下降”的趋势;在2010年之前成熟型城市群的扩张强度最高,2010年之后培育型城市群成为扩张强度最高的类型。② 城市群城市用地扩张总体上呈现不均衡布局的趋势,高速扩张区域主要分布在沿海地区。从全国视角来看,东部高于中、西、东北部,整体城市群快速扩张的中心由东向西移动。③ 城市群城市用地空间扩张模式表现出边缘式和飞地式两种空间扩张模式并存,不同发育等级之间具有明显差异性,成熟型城市群的空间结构较为稳定,其他两种类型的城市群空间结构初具雏形或尚未形成。④ 城市群城市用地扩张“吞没”了郊区和农村地区,破碎化程度、形状的复杂程度较高,景观格局表现出不稳定。⑤ 城市群“人口—土地”协同程度逐步增强,“经济—土地”协同程度整体较高,整体上表现出城市用地扩张质量有所提升。新时期城市群城市用地应严格控制扩张规模,加快中小城市的发展,促进城市群城市用地扩张均衡发展,为城市群国土空间高质量发展提供重要参考。     

矿区废弃土地资源适宜性评价

随着采矿业的发展,我国矿区土地资源破坏相当严重,同时废弃土地资源的复垦利用率又非常低（约１０％）,矿区废弃土地复垦研究工作非常迫切。开展全国矿区废弃土地的适宜性评价研究是其复垦研究的基础,可为其它相关研究提供实时指导。本文正是根据这种需要,通过实地调查研究,运用一定的原则与依据,将矿区废弃土地资源划分为５类２５个亚类,均对每一亚类,作出了相应的适宜性评价,同时还提出了具体的开发利用途径。为矿区废弃土地复垦在技术上的可行性作出了科学的评价,为废弃土地资源的复垦提出有效的开发利用途径,从而为提高土地生产力,缓解土地资源紧缺的矛盾,改善矿区生态环境质量提供有效的政策与技术参考。     

福建省城市土地集约利用研究

为明晰福建省近10年城市土地集约利用状况和时空分异特征,在构建福建省城市土地集约利用评价体系的基础上,运用熵值法对福建省9个设区市市辖区2008~2017年城市土地集约利用状况进行综合评价分析,并引入变异系数揭示其时空变化特征。结果表明:福建省城市土地集约利用水平整体不高,10年间全省整体城市土地集约利用程度变化不明显;福建省城市土地集约类型存在着明显的等级差异,空间差异随着时间的推移略呈扩大的趋势;在空间分布上,东南部沿海地区城市土地集约利用程度明显高于西北部非沿海地区。     

城市建设对暴雨内涝空间分布的影响研究——以武汉市主城区为例

城市内涝灾害频繁,用地开发与空间扩张被普遍认为是其致因之一。对比武汉市遥感数据,1984—2017年,超过30%的自然水体被填占开发,城市建设开发活跃、填湖造陆强度大。论文以武汉市为例,采用二项Logistic模型,定量分析不同降雨强度情景下的内涝影响因素。研究表明,填湖造陆将极大地增加极端降雨情景下城市滨水区域的内涝风险。城市地形地势、排水管网条件、用地类型以及邻域用地结构等因素,也直接影响内涝风险。基于2种不同的用地开发策略,预测城市内涝风险结果显示,城市用地的不当开发将引致严重内涝风险。依据内涝风险的空间分布预测结果,论文提出了相应的改善策略,以为科学地制定防涝减灾规划提供参考。     

海平面上升对中国沿海重要工程设施与城市发展的可能影响

由于自然和人为双重因素作用，２１世纪前半期中国沿海平原地区相对海平面上升幅度可能达到全球平均值的２－３倍，由此将给沿海地区自然环境演变和社会经济发展带来一系列不利影响，本文分析了未来相对海平面上升５０ｃｍ对中国沿海重要的海岸防护、水利与港口码头工程以及城市供水、防洪与滨海旅游业的可能影响方式与程度。     

公交导向型城市开发机理及模式构建

城市交通、土地利用和城市空间结构的相互关系一直是城市地理学、城市规划学和交通地理学研究的核心问题。大容量公共交通、混合型土地开发、宜人的步行环境和高质量的公交服务是公交导向型开发(TOD)模式的主要特点。本文分析了TOD对城市土地利用和城市空间结构的作用机理发现:土地开发强度、土地利用结构以及土地价值是TOD影响城市土地利用的3 个主要方面,而TOD对路网结构、城市规模和城市空间布局的作用进一步影响城市空间结构及其演化。进一步研究发现:大容量公共交通的建设使得城市竞租曲线和开发密度具有多波峰的特点,遵循"随着时间的变化从城市中心向外围递减"的规律。基于中外城市发展背景差异,本文从宏观、中观和微观3 个层面提出建立以大容量公共交通为主轴、以TOD站点为枢纽的轴辐网络状城市空间结构,并提出了TOD站点开发的距离、级差密度、多样性和设计的4Ds原则。     

多中心城市群土地利用/覆被变化地学信息图谱研究——以长株潭城市群为例

多中心城市群具有交通网络发达、功能联系密切、空间多维复合等特征,其土地利用/覆被变化（LUCC）是一个相当复杂的过程。采用地学信息图谱方法,探索城市群LUCC数量结构与时空格局一体化耦合机理,研究用地变化与区域发展互动关系,有助于深入揭示多中心城市群土地利用时空演变规律,为同类城市群的国土空间规划和健康发展提供参考。本文以典型案例长株潭城市群为例,构建1995—2015年四个时期地学信息图谱,并耦合重心转移模型,在总体量化分析基础上,重点从城际与城乡视角深入解析城市群土地利用时空变化特征和一体化发展态势。研究结果表明：① 土地利用总体动态加速演变。四期建设用地扩张年动态度分别为1.06、4.10、2.21和7.39,转移强度动态增加,耕地和林地呈加速减少态势。② 城际与城乡地类图谱转移呈现多维演变。图谱“15（耕地→建设用地）、25（林地→建设用地）、45（水域→建设用地）”重心由株洲城区（Ⅰ 期）向长沙城区（Ⅱ 期和Ⅲ 期）再向湘潭城区（Ⅳ期）迁移,经历“相对均衡-长沙加速崛起-有机均衡”和“城市加速集聚-城乡相对均衡”演变过程。③ 近年来,城际转移强度差异缩小,转移结构分异增加,区域主体功能逐步凸显。同时,外围区县加速发展,城乡一体化水平明显提升。④ 城市群土地利用涨落势图谱与经济社会一体化发展高度耦合,同时耕地保护与高质量发展有待加强。     

Impact of economic development on wetlands in Hangzhou Bay Industrial Belt

Based on Landsat TM images in 2005 and urban planning data of 2005–2020 in Hangzhou Bay Industrial Belt, this paper studied the potential risk of the planned urban construction land extension to the wetlands by employing a GIS spatial analysis method. The results show that: (1) The wetland resources are widely distributed and diverse, with a proximal distribution to present urban construction lands spatially. (2) From 2005 to 2020, the urban construction lands will expand vastly and rapidly, and will take over large areas of wetlands that are mostly the ponds and the aquiculture water areas in the reclamation areas of Hangzhou Bay south coast. Moreover, this change will be spatially uneven obviously, e.g., the most serious recessions of the wetlands are concentrated in Ningbo city, Hangzhou city and Cixi city. (3) Overall, the potential risk to wetlands is very high, and will keep increasing with the trend of urbanization. (4) The quantity and spatial pattern of the planning urban construction land have substantial impacts on the wetland loss. Therefore, some policies and regulations are suggested to coordinate the relationship between urban economic development and wetland resource protection such as adjusting the construction land planning, compensating for wetland occupation as well as constructing wetland parks.     

南京大都市区建设用地扩张特征与机理

作为全球城市化最快的地区之一,中国建设用地的扩张引起了广泛的关注。以长三角北翼中心城市南京为例,利用遥感、土地利用调查等数据研究大都市区建设用地扩张的过程、格局与机理。研究表明,1985-2007年南京市在工业化、城市化和国际化的推动下经济快速增长,引致了建设用地的扩张,年均增长率为3.14%。2001年后随着城市发展模式由单中心向多中心转换,建设用地呈加速扩展趋势。南京市建设用地扩展具有明显的沿长江和南北交通走廊轴向发展的特征。开发区和新城建设是南京市建设用地扩张的主要方式。区、县尺度的回归分析表明,人口增加、全球化是城镇工矿用地扩张的重要推手;经济的服务业化有利于土地集约利用,减少对用地的需求,这种影响在城区更大;在分权化竞争中,都市区政府具有更强的控制力。     

城市生态——生产——生活空间功能定量识别与分析

土地利用多功能性识别是城市用地组织,协调与配置的基础信息源,是判定城市用地内在功能形态,功能组合模式和功能之间动态权衡的关键,具有重要的理论和实践意义,但长期以来并未构建一套可行的识别方法体系.本文从土地功能,生态系统服务和景观功能综合的视角构建城市生态--生产--生活空间功能分类体系,并以生态系统服务价值评估为基础系统整合空间功能价值量核算函数群,通过纵横对比的方法确定空间功能主导类型.研究区实证分析表明,城市生态--生产--生活功能分类体系较好反映了不同地类的功能类型;空间主导功能的识别也与不同地类的功能匹配;同时也发现三生空间的整体毗邻性较低,空间功能的互补和融合性较差的问题;三生空间功能存在一定的空间集聚性.     

Common features and different trajectories of land cover changes in six Western Mediterranean urban regions

Land use and land cover change (LULCC) dynamics have been particularly strong in the Mediterranean region, due to its historical development and to agro-pedoclimatic conditions favorable to human settlement. This area has undergone in the 1950s and the 1980s intense urbanization processes that has followed different trajectories. Urban expansion commonly occurs at the expense of agricultural land, leading to the fragmentation of natural areas and conflicts over access to land resources. These dynamics mainly concern the fringe between urban and agricultural land, e.g. the peri-urban areas usually included within functional urban regions. Here, to identify common features of LULCC in Western Mediterranean urban regions, we investigated two main features: direct changes due to urbanization and indirect changes affecting non-artificial land uses. We compared LULCC dynamics in 6 case studies from the north and south of the Western Mediterranean region: the urban regions of Montpellier and Avignon (France), Pisa (Italy), Madrid (Spain), Meknes (Morocco), and Constantine (Algeria), using a 30-year multitemporal spatial analysis (1980–2010). Two series of Landsat TM images were acquired for each case study and land cover data were analyzed both for dynamics and for land patterns, using landscape and class metrics. We found no significant north-south differences in LULCC dynamics between the investigated Western Mediterranean urban regions. Differences are more pronounced between small–medium cities and large metropolitan areas in type of urban diffusion, which is more sprawled in small–medium cities and more compact in large metropolitan areas. Rather, differences occur in LULCC not directly affected by urbanization, since in Northern Mediterranean urban regions afforestation and abandonment of agricultural areas are prevalent and closer to the urban areas, whereas transformation of natural areas into agricultural ones occurs mainly in Southern Mediterranean urban regions at a similar distance from urban areas than it happens for afforested or abandoned areas. In attempting for the first time to assess LULCC in these Mediterranean urban regions, we provide a preliminary comprehensive analysis that can contribute to the active LULCC research in the Mediterranean basin and that can be easily applied to other Mediterranean urban regions.     

Geologically constrained changes to landforms caused by human activities in the 20th century: A case study from Fukuoka Prefecture,Japan

Human activity has been recognized to be an important geomorphic agent, and the resulting changes to landforms and land cover are regarded as a global problem. Although there has been much research into the relationships between geomorphic processes and types of land use such as agriculture, mining, and urbanization, it is important to clarify spatiotemporal human impacts on topography on a regional scale when predicting future changes in land cover.This study examined changes in land use to clarify the distribution and impact of anthropogenic changes to landforms, as well as the influence of geology on the extent of these changes. In a case study from Fukuoka Prefecture, Japan, changes in land use over the last century were analyzed using a geographic information system (GIS). The study area, which covers approximately 4930 km², has experienced urban development since 1950 and has a current population of over 5 million. Land use data were prepared using paper-based early editions of topographic maps. Subsequently, the distribution of anthropogenic landforms was evaluated by comparing landforms with regional geological data.GIS analysis using our prepared land use data, landform data, and regional geological data has clarified the following characteristics of the study area. (1) Land uses prior to 1950 were constrained by topographic relief. After 1950, land use was characterized by urban sprawl. Urban areas expanded and contained both higher elevations and steeper slopes at their margins. The relationships between land uses and landforms during this urbanization are unclear. (2) The area of urban land increased in the geological regions with Paleogene sedimentary rocks (PSD) and Mesozoic granitic rocks (GR) during the 20th century. The largest coal mining area in Japan was located in the PSD geological regions, and ancient iron working was common in the GR geological regions, particularly during the 7th century. This result indicates that the land use distribution, especially urban areas in sloping terrain, is related to the regional geology. (3) Deforestation related to land use resulted in steeper terrain in forest land in the PSD and GR geological regions. These changes to landforms in forest areas occurred as a result of rapid urban sprawl and have created many new boundaries between forest areas with steeper slopes and urban areas with gentler slopes. This phenomenon may have caused an increase in the frequency of sediment-related disasters.This case study indicates that predictions of anthropogenic changes to landform, which are important for the assessment of global climate change and natural hazards, must clarify the relationships between land uses, landforms, and regional geology.     

多智能体城市土地扩张模型及其应用

传统的城市土地扩张模型多为静态模型,无法呈现空间上每一时间点的土地利用状况,以元胞自动机（Cellular Automata）模型为代表的新型城市土地扩张模型虽然具有动态特性,但其无法描述影响城市土地扩张的智能体（Agent）之间所产生的多元变化结果。以多智能体系统（Multi—Agent System）理论为基础,建立城市土地资源时间和空间配置规则,构建了动态且能描述影响城市土地扩张的智能体（Agent）间互动关系的城市土地扩张模型,并以长沙市区为例,应用所构建之模型进行了城市土地扩张的实证分析。结果表明：该模型可以反映城市土地扩张的基本特征和规律．对于解释城市土地扩张的成因、理解智能体行为对城市土地扩张过程的影响是合适的。并且将模拟结果与遥感土地利用解译结果对比．1998年、2001年、2005年城市土地扩张模拟的点对点精度均达到68％以上,从而能够为政府和城市规划者制定用地政策提供辅助决策支持。     

洞庭湖地区耕地功能时空演变特征及影响因素研究

耕地功能时空演变规律及影响因素研究是凸显耕地价值与作用、推动地区协调发展的重要科学依据。综合运用熵值法、地理探测器模型等方法,以湖南省洞庭湖地区24个县市区为研究区域,对该地区耕地功能的时空演变、空间分异及其影响因素进行研究。结果表明：① 1998—2018年洞庭湖地区耕地经济生产功能整体呈增强趋势,主要集中于洞庭湖地区中部、西南部等农业基础较好的区域;社会保障功能整体增强明显,仅有临澧县、津市市和鼎城区3个地区功能强度有所减弱;生态维护功能空间格局变化较小,整体呈中间高两边低的态势。② 自然地理条件是早期影响地区耕地功能的主要因素,随时间推移其影响能力逐渐弱化;社会经济发展到一定阶段,社会经济因素对耕地功能空间分异的影响能力逐渐增强,并凸显出决定性作用;耕地利用水平的不断提升,对耕地功能空间分异影响能力逐渐增强;不同因子之间的交互作用能够明显增强对洞庭湖地区耕地功能空间分异的解释力,共同推动地区耕地功能多元化发展。     

1985-2015年京津冀地区城市建设用地时空演变特征及驱动因素研究

长期以来土地利用/覆被变化一直是全球关注的热点话题,研究城市建设用地时空演变特征,准确定位城市功能是促进城市科学、持续发展的重要保障。以京津冀地区13个城市1985-2015年的城市建设用地为研究对象,运用定量与定性结合的方法,分析城市建设用地时空演变特征;利用多元线性回归、通径分析、地理探测器等方法,诊断城市建设用地时间演化过程与空间演变格局分异的主导驱动因子,通过深入分析各主导因子的驱动机制,对京津冀的城市发展进行功能定位。结果表明：① 京津冀地区城市建设用地的扩张规模、速率、方向和稳定性等存在明显的差异,将城市类型分为协调稳定型、协调波动型、不协调稳定型、不协调波动型;② 城市建设用地时间演化过程的主导驱动因子包括GDP指数、人口密度指数、财政收入指数,空间演变格局差异的主导因子包括到城市中心距离、到主要河流距离、到主要公路距离;③ 根据分析结果,将京津冀地区13个城市规划为核心经济引领城市、重点经济拓展城市和稳定经济涵养城市,对促进京津冀地区协调统筹和一体化发展具有参考价值。     

南京市主城区住宅地价的时空演变

城市地价在空间、时间分布上具有较强的关联性和特殊性,随着城市建设的快速发展和土地市场的不断发育,城市地价的时空变化日趋复杂。本文以南京市主城区为例,基于城市地价动态监测数据,运用统计分析方法和克里金插值方法,研究城市住宅地价时空演变特征。研究表明:从宏观上讲,地价时间上演变受宏观经济影响较大,大的经济形势、房地产市场的变动,对地价变化影响显著。从中观上讲,地价空间上演变主要体现在城市内部的区位条件、交通条件、城市规划、公用设施状况和环境条件等的影响。上述两者共同作用于地价的变化,并且两者相互关联、密不可分。通过城市地价的时空演变研究,以期快速、直观、准确地反映城市地价变化,为城市地价的宏观调控、合理利用土地资源提供参考。